Traverse rods are conventionally operated by draw cords which extend downwardly from a pulley case at one end of the rod. When such rods are intended for home installation, they usually are made up of semi-tubular (C or inverted U-shaped in cross section) telescoping sections having a pulley case at each end of the rod, and with the rod being supported at each end by wall brackets. A pair of master carriers control closing and opening the curtain with the draw cord being releasably connected to each. The draw cord forms a loop within the rod over the pulleys at each end with the masters connected respectively to opposite sides of the loop. In this way, pulling the draw cord in one direction opens the curtain while the other direction closes it. The installation and length adjustment of the rod are easily accomplished. First the wall brackets are mounted. Next the rod length is adjusted and the rod is then mounted on the brackets, usually by a simple snap fit. During the length adjustment, the draw cord must be free of one of the master carriers. After the rod has been mounted, the master carriers are then moved to the fully opened position, all slack in the draw cord is removed, and the draw cord is secured to the other master carrier. At this point, the rod is in condition for use, and closing the curtain will bring the two master carriers together at the center of the window (or other opening).
Although there has long been a demand for motor driven traverse rods, and various types have been sold over the years, the previously known motor driven traverse rods have been expensive and have not been suitable for consumer installation, and, as a result such devices have been employed only by professional interior decorators in isolated and high priced installations.
The problems involved are as follows. First, the drive mechanism must be a positive drive in the sense that it cannot slip at any point or else the curtain will not close or open fully. For this reason, in one prior installation, a double threaded worm gear extending the full length of the rod was employed to drive the master carriers. A second problem is that the rod must be readily adjustable in length. This problem is complicated by the need for a positive drive. Obviously, the simple draw cord arrangement of the conventional traverse rod would be unsuitable because there would be inevitable slippage between a motor drive and such a cord. Likewise, the double threaded worm gear arrangement of the prior art would have to be cut and adjusted professionally in the field, and would not be suitable for length adjustment by the average consumer. A third problem related to the ease of installation is that of where to mount the motor and control elements. The prior installation's special arrangements sometimes involving a recess in the adjacent wall, are required.
It is, therefore, an object of this invention to provide a motor driven traverse rod which is relatively inexpensive, in which the drive is completely positive, and which can be adjusted for length during installation, with the same ease as the length adjustment of a conventional telescoping traverse rod. A further object is to adapt a motor drive for combination with a conventional telescoping traverse rod without any need for special measuring, cutting or hiding power or control components, and in which the steps involved in installation are essentially the same as for conventional telescoping traverse rods.